Photophysics of Biological Active Chromophores Confined in Graphene-Oxide Mediated Reverse Micelles

Abstract

In this thesis, the entrapment of anti-fungal, anti-bacterial, non-fluorescent cationic dye molecules Crystal Violet (CV) and Acridine Orange (AO) in presence of bio-mimetic confined Reverse-Micelle aggregates has been studied. The photophysical characteristic behaviour of CV and AO has been carried out by varying different kinds of surfactants (named as Aerosol-OT, SDS, SOS) forming reverse micelles. The main objective is to improve the solubility and fluorescence properties of the studied fluorophores in presence of bio-mimic confined aqueous and non-aqueous reverse micelles and deciphers different kinds of non-covalent solute-solvent interactions. To interpret the result, steady state absorption and fluorescence emission techniques have been carried out. In methanol, CV and AO molecule exhibits non-fluorescent in nature. The value of fluorescence quantum yield (Φ) is ~10-4. But after the confinement of the molecules (CV and AO) in different reverse micelle mediums, they become highly fluorescent in nature. It has also been detected that in presence of different reverse micelle aggregates, both CV and AO molecules exhibits remarkable enhancement of absorption and fluorescence emission spectral behaviour. Moreover, the role of the GO in aqueous medium was also explored. Presence of GO in RMs assemblies caused quenching in absorption, fluorescence emission and the fluorescence quantum yield values. This result clearly interpreted that GO acts as quencher and have ability to release the studied molecules from the RMs assemblies. For that reason, the highly fluorescent nature of the molecules again turns into non-fluorescent in presence of GO. The work involved in this thesis might be valuable for potential targeted drug-delivery implications, detection analysis, sensors in physiological systems.